By the time Ive drunk it that's when I think to myself
当我喝醉的时候 我都会想
"I said were not going to do this and now Im doing it."
"我每次都说不要喝醉 可现在又醉了"
"Today Im not going to want to drink I'm not going to drink."
"今天我不要喝 今天我不要喝"
And then by evening youre thinking quite a lot about it.
然后那天晚上又醉了 你会反思很多
Despite the doctors advice that I should cut down -I hadn't.
虽然医生建议我应该少喝 但我没有
But why not? It's not as if the rules are difficult to understand
为什么呢 并不是我不理解医生的规则
and I follow other rules OK green lights healthy food...
我遵守其它规则 如红绿灯和健康食品
but despite understanding the threat to my body my brain wants to carry on regardless.
但在酒精上 我却不愿改变
So why is this effect on me so powerful?
到底是什么力量影响着我呢
At the addiction centre in Washington
在华盛顿的戒瘾中心
they've devised a way of looking at the brain to answer precisely this question -
他们已通过对大脑的研究回答这问题
what happens when alcohol hits it?
当酒精影响大脑时 到底发生了什么
This is cutting-edge science
这是一个前端的科学问题
and I'm going to be on the end of it.
而我将去看看它的答案
I guess on the one hand youd think it would be quite easy to study the effects of alcohol
也许我们觉得酒精对大脑的影响很简单

from the human drinker's point of view.
从喝酒者的角度来看

重点解释：

1.by the time到…时候

例句：By the time I came on the scene, it was all over.
我来到时，一切都结束了。

2.cut down削减； 删减

例句：He has to cut down on the consumption of meat.
他不得不减少吃肉。

3.carry on 继续进行；从事，经营

例句：We'll carry on as arranged and they can do their worst.
我们还按我们的计划办事,他们想怎么使坏就随他们便吧。